To be fair, the size of the gender gap doesn't really mean anything in terms of the election outcome. The Democrats have picked an all-male ticket and that's their choice. If they lose because of that, they have only themselves to blame.
As for undecideds being minorities, it's the same as in Georgia, I wouldn't put too much stock in it. Minorities are less likely to be informed about politics to begin with or care. It's just a sign that these voters are less likely to turn out. I wouldn't be surprised if many of these people simply don't show up.
As a Floridian Democrat who didn't even favor the selection of Chris King, I can assure you nobody is gonna decide not to vote for Gillum b/c he picked another guy as his running mate.